TACTILE SENSE PRESENTATION DEVICE AND METHOD OF DRIVING TACTILE SENSE PRESENTATION DEVICE
A plurality of X electrodes and a plurality of Y electrodes arranged on a support substrate of the tactile sense presentation device are divided into M groups (here, M≧2, M=4 in FIG. 14). When a presentation content of a tactile sense transits from the N-th frame to the (N+1)-th frame, the tactile sense presentation device, first, sets electrodes belonging to a group 1 to a floating state for a predetermined time and then, connects each electrode to an AC voltage signal source or the ground so as to present a tactile sense in the (N+1)-th frame. The tactile sense presentation device sequentially performs this operation for each group, and, when the operation of a group M ends, a transition between frames ends, and the movement of the target area that is an area in which a texture sense is presented is completed. There is no case where all the electrodes are in the floating state together, and there is no interruption of the texture sense.
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This non-provisional application claims priority under 35 U.S.C. §119(a) on Patent Application No. 2015-111564 filed in Japan on Jun. 1, 2015, the entire contents of which are hereby incorporated by reference.
BACKGROUND1. Technical Field
The present invention relates to a tactile sense presentation device presenting a tactile sense to a human body using static electricity and the method of driving a tactile sense presentation device.
2. Description of the Related Art
The background technology of the present invention is a tactile sense presenting technology presenting a tactile sense to a human body through vibrations of an attractive force due to static electricity and being capable of presenting a local tactile sense. In “H. Haga et al., “Electrostatic Tactile Display Using Beat Phenomenon of Voltage Waveforms,” SID 2014 Digest, pp. 623-626 (2014)”, such a tactile sense presenting technology is disclosed. More specifically, in a tactile sense presentation device, X electrodes are arranged in parallel with the longer side of a support substrate having a rectangular shape, and Y electrodes are arranged in parallel with the shorter side of the support substrate. Then, an AC (Alternate Current) voltage signal of 1000 Hz is applied to the X electrodes from a first AC voltage signal source, and an AC voltage signal of 1240 Hz is applied to the Y electrodes from a second AC voltage signal source. As a result, a texture sense is presented to an area in which the electrodes having AC voltage signals applied thereto intersect with each other. The area in which the texture sense is presented is set as a target area. In the target area, an electric beat vibration of 240 Hz is generated. When a user slides a finger or the like on the surface of the target area, an electrostatic force due to a beat vibration generates a frictional force between the skin and the surface of the target area. A user can perceive the frictional force as a texture sense.
At this time, in an area (hereinafter, referred to as a single signal area) in which an AC voltage signal is applied to only one of the X electrode and the Y electrode, no texture sense is presented. The reason for this is that the frequency of a vibration occurring in the single signal area is beyond the range of frequencies that can be perceived by a person as a texture sense. According to the characteristics described above, a conventional technology presents a texture sense only to the target area, in other words, is capable of giving a local tactile sense presentation.
SUMMARY OF THE INVENTIONThe inventors of the present application produced a prototype of a tactile sense presentation device by referring to “H. Haga et al., “Electrostatic Tactile Display Using Beat Phenomenon of Voltage Waveforms,” SID 2014 Digest, pp. 623-626 (2014)”.
In
The tactile sense presentation device 1 can change the position of the target area by changing the electrodes to which the AC voltage signals are applied. In addition, the target area can be continuously moved like in a moving image. Since the support substrate 2, the X electrodes 3 and the Y electrodes 4 are transparent, the tactile sense presentation device 1 can be used with being overlapped with a visual display. In this way, a device presenting a tactile sense corresponding to an image displayed on the visual display can be configured.
However, the inventors of the present application found following two problems. When a target area is moved by the tactile sense presentation device 1, (1) an unnecessary texture sense in a single signal area is presented and (2) a texture sense in the target area is interrupted. In a case where the target area is stopped, no texture sense is present in the single signal area. However, in a case where the target area is continuously moved like in a moving image, a texture sense is presented also in the single signal area. In other words, a tactile sense that is unnecessary in an area other than the target area is presented, and the characteristic of “the localization of a tactile sense” in the conventional technology is degraded. In addition, since the texture sense of the target area is interrupted when the target area is moved, a user feels a sense of incongruity. In other words, in the target area, an unnecessary tactile sense of the interruption of the texture sense is presented.
According to the present disclosure, there is provided a tactile sense presentation device including: a support substrate; a plurality of X electrodes that are arranged on the support substrate; a plurality of Y electrodes that are arranged on the support substrate and are insulated from the X electrodes; a switching circuit that connects each of the X electrodes and each of the Y electrodes to an AC voltage signal source or a reference voltage source; and a control unit that is used for controlling the switching circuit, wherein the X electrodes and the Y electrodes are divided into at least two groups, and the control unit changes states of the X electrodes and the Y electrodes for one group each time.
According to the present disclosure, there is provided a method of driving a tactile sense presentation device including: a support substrate; a plurality of X electrodes that are arranged on the support substrate; a plurality of Y electrodes that are arranged on the support substrate and are insulated from the X electrodes; a switching circuit that connects each of the X electrodes and each of the Y electrodes to an AC voltage signal source or a reference voltage source selectively; and a control unit that is used for controlling the switching circuit, the method including: dividing the X electrodes and the Y electrodes into at least two groups; and driving the X electrodes and the Y electrodes by changing states of the X electrodes and the Y electrodes for one group each time.
In the present disclosure, the plurality of X electrodes and Y electrodes of the tactile sense presentation device are divided into a plurality of groups. The tactile sense presentation device, when a target area presenting a texture sense is moved, causes electrodes belonging to one group to be in a floating state, and, after maintaining the floating state for a constant time, connects each electrode to one of an AC voltage signal source and the ground so as to be in correspondence with a target area after the movement. The tactile sense presentation device, next, causes electrodes belonging to another one group to be in the floating state. The tactile sense presentation device sequentially performs the operation described above for each group, thereby moving the target area.
By using the method of driving a tactile sense presentation device described above, the number of electrodes that are simultaneously caused to be in the floating state is divided in accordance with a group division number. Accordingly, the area that is simultaneously influenced by the floating state is decreased, and a voltage applied to the electrodes that are in the floating state is not zero in accordance with capacitive coupling. For this reason, an unnecessary tactile sense is not presented, and a texture sense is continuously presented in the target area.
The above and further objects and features of the disclosure will more fully be apparent from the following detailed description with accompanying drawings.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the disclosure.
Hereinafter, embodiments of the present invention will be specifically described with reference to drawings.
First EmbodimentIn the tactile sense presentation device 100, all the X electrodes 103 and all the Y electrodes 104 are divided into a plurality of groups. When the number of groups into which the electrodes are divided is defined as M, M has a minimum of 2 and an undetermined upper limit. However, in a case where M is small, an effect of decreasing an unnecessary tactile sense is weakened. On the other hand, as M increases, a transition period of a frame increases, and accordingly, there is concern that smooth movement of a target area is disturbed. In a test using a tactile sense presentation device according to the present embodiment, a sufficient effect has been checked with M=4, and thus, also in the first embodiment, M=4. In this embodiment, the X electrodes 103 and the Y electrodes 104 are divided such that electrodes adjacent to each other belong to mutually-different groups.
While an example in which one node of the switching device 114 is connected to the ground has been described, the position to which the node is connected is not limited to the ground. For example, the node may be connected to a DC (Direct Current) voltage source of other than zero volts or a third AC voltage signal source. An AC voltage signal generated by the third AC voltage signal source does not independently present a texture sense, and no texture sense is presented even in the case of generating a beat together with a first AC voltage signal or a second AC voltage signal. The ground that is a DC voltage source of zero voltage, the DC voltage source of other than zero volts, and the third AC voltage signal source are regarded as reference voltage sources. In other words, a configuration in which the node is connected to the reference voltage source belongs to the present embodiment.
Next, the operation of the tactile sense presentation device 100 will be described.
Hereinafter, the operation of the tactile sense presentation device 100 will be described along the flow of the flowchart illustrated in
Subsequently, similarly, the switching devices 113 and 114 connected to the electrode of the group 2 are caused to be in the open state, and the electrodes of the group 2 are in the floating state. After the floating state is maintained for a predetermined time, similarly, each switching device 113 connected to the electrode corresponding to the target area of the (N+1)-th frame among the electrodes of the group 2 is caused to be in the conduction state, and an AC voltage signal is applied to the electrode corresponding to the target area. At the same time, each switching device 114 connected to the electrode not corresponding to the target area of the (N+1)-th frame among the electrodes of the group 2 is caused to be in the conduction state, and accordingly, the electrodes not corresponding to the target area are connected to the ground.
The operation described above is repeated for each group, and, in the first embodiment, when the operations up to the group 4 are completed, the transition from the N-th frame to the (N+1)-th frame is completed. In accordance with the transition from the N-th frame to the (N+1)-th frame, the target area is moved. In addition, there is a target area that does not move. Thereafter, until information of the next frame is input to the control unit 107, the state of each electrode of the (N+1)-th frame is maintained.
Next, the time during which the electrodes are maintained in the floating state will be described. In this embodiment, as illustrated in
In a switching device, a maximum turn-off time (Maxtoff) is defined in the specifications. The maximum turn-off time is a maximum time required for the switching device to transit to the open state after the switching device receives a control signal used for causing the open state in the conduction state. In this embodiment, the polarity of the control signal of the switching devices 113 and 114 is normally open. When the control signal is at the low level, the switching devices 113 and 114 are open. On the other hand, when the control signal is at the high level, the switching devices 113 and 114 are conductive.
For example, in a case where a certain electrode transits from a state of being connected to the AC voltage signal source to a state of being connected to the ground, the control unit 107, after transmitting a control signal used for causing the open state to the switching device 113, stands by for a time until the switching device 113 is in the completely open state after the fall of the transmitted control signal, in other words, for the maximum turn-off time (Maxtoff) and then transmits a control signal used for causing the conduction state to the switching device 114. By configuring as such, a situation in which the switching device 113 and 114 are simultaneously in the conduction state can be avoided.
Here, a time from a moment at which a signal transmitted through the control signal line 115 to the switching device 113 starts to fall to a moment at which a signal transmitted through the control signal line 116 to the switching device 114 starts to rise is defined as a time T. By setting the time T so as to satisfy the condition of the following Equation (1), the switching circuit 112 illustrated in
(Maxtoff)<T (1)
Hereinafter, in the tactile sense presentation device 100, a case where a target area is moved will be illustrated as an example, a drive method of a case where an unnecessary tactile sense is presented and a drive method according to this embodiment are compared with each other, and effects acquired in this embodiment will be described.
First, the operation of the drive method of a case where an unnecessary tactile sense is presented will be described.
As illustrated in
In the drive method of a case where an unnecessary tactile sense is presented, when a transition between frames is made, all the electrodes are caused to be in the floating state together. For this reason, when a time during which the electrodes are maintained to be in the floating state is TF, the transition period of the frame is equal to the time TF. Since all the electrodes are caused to be in the floating state together in this transition period, as illustrated in
In a case where the target area does not move, and the floating state of the electrodes does not occur, a texture sense is not generated in a single signal area. In such a case, an AC voltage signal is continuously applied to the single signal area, and the spectrum of the frequencies of vibrations is concentrated on a frequency (for example, 2000 Hz) that is twice the frequency of the AC voltage signal. Since the frequency of 2000 Hz or the like is not sensed by a human body, a texture sense is not generated. On the other hand, in a case where the target area is moved, all the electrodes are in the floating state all together at the time of the movement, and an interruption of the AC voltage signal occurs in the single signal area. Accordingly, the spectrum of the frequencies of vibrations occurring in the single signal area is widely distributed having the frequency that is twice the frequency of the AC voltage signal as its center and is distributed also within the range of 10 to 1000 Hz which is sensible to the human body. For this reason, it is assumed that a texture sense is presented in the single signal area.
Next, the effects of a case where a drive method according to this embodiment is used will be described.
In a state in which the N-th frame is presented, an AC voltage signal is applied to each electrode. As illustrated in
Here, a time during which the electrode is maintained to be in the floating state is denoted by TH. For example, TH=5 ms. The value of TH is different depending on the specifications of the switching device. According to the drive method of this embodiment, the floating state is formed for each group, and accordingly, the transition period of frames is equal to four times the time TH. During the transition period, also in a state in which the electrodes of one group is in the floating state, an AC voltage signal is constantly applied to the electrodes of the other three groups. In other words, the area that is simultaneously influenced by the floating is ¼ of that according to the drive method of a case where an unnecessary tactile sense is presented. In addition, the inventors of the present application have checked that an electrode that is in the floating state is capacitive-coupled with neighboring electrodes of the other groups, to which an AC voltage signal is applied, and the voltage thereof is not zero.
Since the area influenced by the floating becomes ¼, an area in which vibrations having frequencies of 10 to 1000 Hz sensed by the human body in accordance with an occurrence of the interruption of the AC voltage signal occur is decreased. In addition, since the voltage applied to the electrode that is in the floating state is not zero, the intensity of vibrations having frequencies of 10 to 1000 Hz decrease. According to these two effects, a texture sense presented in the areas 133a, 133b, 133c, and 133d is assumed to decrease to a level that cannot be perceived by a human body. Actually, the inventors of the present application have checked that a texture sense is not perceived in the areas 133a, 133b, 133c, and 133d. In this embodiment, simultaneous applications of an AC voltage signal over a plurality of electrodes neighboring to each other included in an area range in which a tactile sense can be perceived by a person do not occur, and, also in the case of no application of an AC voltage signal, the AC voltage applied to an electrode is not zero in accordance with an influence of the other groups, whereby it is assumed that an unnecessary tactile sense is not presented in an area other than the target area.
A tactile sense presentation device according to a second embodiment will be described.
As described above, in the second embodiment, the X electrode driving circuit 105 and the Y electrode driving circuit 106 according to the first embodiment illustrated in
A tactile sense presentation device according to a third embodiment will be described.
Each X electrode 303 is connected to the output terminal 111 illustrated in
In the first and second embodiments, in a case where the size of the support substrate is increased, a pitch between the electrodes increases. According to the third embodiment, by configuring one electrode using a plurality of sub electrodes, even when the size of the support substrate 301 is increased, the pitch of the electrodes can be configured to be fine without increasing the number of output terminals arranged on the support substrate 301. In the tactile sense presentation device according to the third embodiment, by performing an operation similar to that according to the first embodiment, effects similar to those of the first embodiment are acquired. Thus, the operations and the effects according to the third embodiment will not be described.
Fourth EmbodimentA tactile sense presentation device according to a fourth embodiment will be described.
Hereinafter, in describing an example of the operation according to the fourth embodiment, two X electrodes 103 adjacent to each other represented as Xm and Xm+1 among X electrodes 103 illustrated in
0≦TI<TH (2)
As above, while the operation of the tactile sense presentation device 400 regarding the X electrodes 103 has been described, also regarding the Y electrodes 104, the tactile sense presentation device 400 similarly operates. In the fourth embodiment, the tactile sense presentation device 400 performs an operation similar to that according to the first embodiment except that times in which the electrodes are in the floating state partly overlap each other between mutually-different groups. The effects of the present embodiment of not presenting an unnecessary tactile sense and presenting a texture sense that is not interrupted in the target area are acquired in a case where the time TI is at least slightly smaller than the time TH. In other words, in a case where periods in which floating states are formed at least deviate from each other between mutually-different groups, the effects are acquired. These effects increase as the time TI decreases and are maximum at the time of TI=0.
As above, also according to the fourth embodiment, effects similar to those of the first embodiment can be acquired. In addition, according to the fourth embodiment, the times in which the electrodes are in the floating state partly overlap each other between mutually-different groups, and accordingly, a time required for the presented content of a tactile sense to transit from the N-th frame to the (N+1)-th frame is shorter than that of the first embodiment. Since the frame transition of the presented content of a tactile sense is performed in a short time, the target area can be moved more smoothly.
Fifth EmbodimentA tactile sense presentation device according to a fifth embodiment will be described.
As above, in the fifth embodiment, the distance between electrodes to which are arranged adjacent is sufficiently fine, and the electrodes adjacent to each other are continuously caused to belong to the same group. When the target area is moved, the electrodes belonging to the same group are in the floating state at the same timing. However, in a case where electrodes that are continuously adjacent to each other belong to the same group, like the X electrodes Xp+1 to Xp+3 illustrated in
The effect of decreasing an unnecessary tactile sense in the present embodiment is acquired by decreasing an area simultaneously receiving the influence of the electrodes being in the floating state on the surface of the tactile sense presentation device 500. In a case where a person's finger is in touch with the surface of the tactile sense presentation device 500, when an area corresponding to electrodes belonging to a plurality of groups having mutually different timings at which the floating state is formed is included in a contact area, electrodes corresponding to the whole contact area are not simultaneously in the floating state, and an effect of decreasing an unnecessary tactile sense is acquired. In a case where the contact area of the person's finger is assumed to be a circle having a diameter of 10 mm, in order to allow the area corresponding to the electrodes belonging to the plurality of groups to be included in the contact area, it is preferable that the range of the electrodes included in the same group is 5 mm or less. Accordingly, it is preferable that a distance between the first electrode and the last electrode included in the electrodes, which are continuously adjacent to each other, belonging to the same group is 5 mm or less.
As above, also in the fifth embodiment, effects similar to those of the first embodiment are acquired. In addition, in the fifth embodiment, since the X electrodes 503 and the Y electrodes 504 are arranged at a relatively fine pitch, the tactile sense presentation device 500 can present a tactile sense having high resolution.
In the first to fifth embodiments, while an example in which the tactile sense presentation device is combined with the visual display has been described, the tactile sense presentation device may not be configured not to be combined with a visual display. For example, the tactile sense presentation device may be a tablet device that presents a tactile sense without displaying an image.
The tactile sense presentation device according to the present disclosure has advantages of being capable of presenting a local tactile sense when a target area presenting a texture sense is moved like a moving image and being capable of continuously presenting a texture sense in the target area without interrupting the texture sense. Accordingly, the present disclosure effectively functions for a device that includes a visual display such as a liquid crystal display and presents a content in which an object is moved like a moving image such as, particularly, a smartphone, a tablet terminal, an amusement device, a car navigation device, and the like. In addition, the tactile sense presentation device can be used without being combined with a visual display.
In the tactile sense presentation device according to the present disclosure, an unnecessary tactile sense is not presented when a target area in which a tactile sense is presented is moved. In addition, a tactile sense presentation device capable of continuously presenting a texture sense in the target area without interrupting the texture sense can be provided.
It is noted that, as used herein and in the appended claims, the singular forms “a”, “an”, and “the” include plural referents unless the context clearly dictates otherwise.
As this invention may be embodied in several forms without departing from the spirit of essential characteristics thereof, the present embodiment is therefore illustrative and not restrictive, since the scope of the invention is defined by the appended claims rather than by the description preceding them, and all changes that fall within metes and bounds of the claims, or equivalence of such metes and bounds thereof are therefore intended to be embraced by the claims.
Claims
1. A tactile sense presentation device, comprising:
- a support substrate;
- a plurality of X electrodes that are arranged on the support substrate;
- a plurality of Y electrodes that are arranged on the support substrate and are insulated from the X electrodes;
- a switching circuit that connects each of the X electrodes and each of the Y electrodes to an AC voltage signal source or a reference voltage source; and
- a control unit that is used for controlling the switching circuit,
- wherein the X electrodes and the Y electrodes are divided into at least two groups, and
- the control unit changes states of the X electrodes and the Y electrodes for one group each time.
2. The tactile sense presentation device according to claim 1, further comprising:
- an electrode driving circuit that includes the AC voltage signal source, the reference voltage source, and the switching circuit,
- wherein the control unit provides the electrode driving circuit with instruction specifying a target area included in an area where the plurality of X electrodes and Y electrodes are corresponding in correspondence with information input from the outside,
- the electrode driving circuit applies a voltage signal having a first frequency to the X electrodes corresponding to the target area,
- the electrode driving circuit applies a voltage signal having a second frequency to the Y electrodes corresponding to the target area, and
- the electrode driving circuit generates an electric beat vibration in the target area based on an absolute value of a difference between the first and second frequencies and presents a texture sense using an electrostatic force caused by the electric beat vibration.
3. The tactile sense presentation device according to claim 2,
- wherein the electrode driving circuit does not present an unnecessary tactile sense in an area other than the target area.
4. The tactile sense presentation device according to claim 3,
- wherein the electrode driving circuit connects the X electrodes and the Y electrodes not corresponding to the target area to the reference voltage source, and
- the electrode driving circuit changes the states of the X electrodes and the Y electrodes corresponding to the target area at different timings for each of the groups.
5. The tactile sense presentation device according to claim 2,
- wherein the electrode driving circuit does not present an unnecessary tactile sense for the target area.
6. The tactile sense presentation device according to claim 5,
- wherein the electrode driving circuit changes timing at which connections of the X electrodes and the Y electrodes corresponding to the target area to the AC voltage signal source are open for each of the groups.
7. The tactile sense presentation device according to claim 1,
- wherein the X electrodes adjacent to each other and the Y electrodes adjacent to each other belong to mutually-different groups.
8. A method of driving a tactile sense presentation device including:
- a support substrate;
- a plurality of X electrodes that are arranged on the support substrate;
- a plurality of Y electrodes that are arranged on the support substrate and are insulated from the X electrodes;
- a switching circuit that connects each of the X electrodes and each of the Y electrodes to an AC voltage signal source or a reference voltage source selectively; and
- a control unit that is used for controlling the switching circuit, the method comprising:
- dividing the X electrodes and the Y electrodes into at least two groups; and
- driving the X electrodes and the Y electrodes by changing states of the X electrodes and the Y electrodes for one group each time.
9. The method according to claim 8, further comprising
- changing the states of each of the X electrodes and each of the Y electrodes to one of a state of being connected to the AC voltage signal source or the reference voltage source and a state of floating.
10. The method according to claim 9, further comprising
- changing the states of each of the X electrodes and each of the Y electrodes from the state of being connected to the AC voltage signal source or the reference voltage source to the state of floating, and thereafter from the state of floating to the state of being connected to the AC voltage signal source or the reference voltage source.
11. The method according to claim 8, further comprising
- dividing the X electrodes and the Y electrodes such that the X electrodes adjacent to each other and the Y electrodes adjacent to each other belong to mutually-different groups.
12. A tactile sense presentation device, comprising:
- a support substrate;
- a plurality of X electrodes that are arranged on the support substrate;
- a plurality of Y electrodes that are arranged on the support substrate and are insulated from the X electrodes;
- a switching circuit that turns on/off an electric connection between each of the X electrodes and the Y electrodes and an AC voltage signal source and turns on/off an electric connection between each of the X electrodes and the Y electrodes and a reference voltage source; and
- a control unit that is used for controlling the switching circuit,
- wherein each of the X electrodes and the Y electrodes takes one of a first state of being connected to one of the AC voltage signal source and the reference voltage source and a second state of not being connected to both of the AC voltage signal source and the reference voltage source, and
- the control unit controls the switching circuit such that, between at least some electrodes adjacent to each other among the X electrodes and the Y electrodes, periods of the second state partly overlap each other or do not overlap each other.
13. A tactile sense presentation device according to claim 12,
- wherein between at least some electrodes adjacent to each other among the X electrodes and the Y electrodes, when a length of a period in which periods of the second state overlap each other is TI, and a length of a period of the second state is TH, “O<TI<TH” is satisfied.
Type: Application
Filed: May 26, 2016
Publication Date: Dec 1, 2016
Patent Grant number: 10175758
Applicant: NLT TECHNOLOGIES, LTD. (Kawasaki)
Inventors: Daisuke SUGIMOTO (Kawasaki), Hiroshi HAGA (Kawasaki), Jiro YANASE (Kawasaki)
Application Number: 15/165,230